Over the years, mobile devices such as smartphones have become widespread. With the rapid development in communication technology, smartphones have become an integral part of many people's lives given the portability, the convenient access to the Internet, and the growing number of applications available on smartphones. Today, individuals can perform a wide range of functions such as online banking, shopping, etc. via smartphones. Many smartphone browsers can be configured by users to remember passwords, form data, and other information to provide quick and easy access to account information, e-mails, and so on. Furthermore, smartphones typically store the names and addresses of contacts. In this regard, smartphones generally contain sensitive information. Smartphones typically allow users to lock their phones such that a passcode or finger gesture tracing a pre-defined pattern must be entered in order to unlock the phone. However, various perceived shortcomings exist with these security mechanisms.